L6740LTR STMicroelectronics, L6740LTR Datasheet - Page 36

• Manufacturer Part Number: L6740LTR
• Description: IC HYBRID CONTROLLERS 48TQFP
• Manufacturer: STMicroelectronics

Specifications of L6740LTR

• Applications: Hybrid Controllers
• Voltage - Supply: 9 V ~ 15 V
• Current - Supply: 20mA
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Number Of Outputs: 2
• Output Current: 170 A
• Input Voltage: 13.2 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-6298-2

Main oscillator
8
36/44
Main oscillator
The controller embeds a dual-oscillator: one section is used for the CORE and it is a multi
phase programmable oscillator managing equal phase-shift among all phases and the other
section is used for the NB section. Phase-shift between the CORE and NB ramps is
automatically adjusted according to the CORE phase # programmed.
The internal oscillator generates the triangular waveform for the PWM charging and
discharging with a constant current an internal capacitor. The switching frequency for each
channel, F
section at the load side results in being multiplied by N (number of configured phases).
The current delivered to the oscillator is typically 22 μA (corresponding to the free running
frequency F
connected between the OSC pin and SGND. Since the OSC pin is fixed at 1.240 V, the
frequency is varied proportionally to the current sunk from the pin considering the internal
gain of 6.8 kHz/μA (See
Connecting R
according to the following relationships:
Figure 15. R
F
SW
=
150kHz
SW
SW
, is internally fixed at 150 kHz: the resulting switching frequency for the CORE
OSC
OSC
= 150 kHz) and it may be varied using an external resistor (R
+
--------------------------- - 6.8
R
to SGND the frequency is increased (current is sunk from the pin),
1.240V
OSC
vs. switching frequency
(
kΩ
Figure
)
⋅
kHz
---------- -
15).
μA
=
150kHz
+
8.432 10
---------------------------- -
R
OSC
(
⋅
kΩ
6
)
OSC
) typically
L6740L